1. Field of the Invention
The present invention relates to an apparatus for cutting a liquid crystal display panel and a method thereof, and more particularly, to an apparatus and method for cutting a liquid crystal display panel that individually cuts liquid crystal display panels formed on a large glass substrate into unit liquid crystal display panels.
2. Description of the Related Art
In general, a liquid crystal display device displays a desired image by individually supplying a data signal, according to image information, to liquid crystal cells arranged in a matrix form and controlling light transmittance of the liquid crystal cells.
To improve yield in fabricating a liquid crystal display device, a plurality of thin film transistor array substrates are formed on one large mother substrate, and a plurality of color filter substrates are formed on another mother substrate. The two mother substrates are then attached thereby simultaneously forming a plurality of liquid crystal display panels. Thus, a process for cutting the liquid crystal panel into a plurality of unit panels is required.
The liquid crystal display panels formed on the large mother substrate are cut into a plurality of unit panels by first performing a scribing process where a scribing line on a surface of the mother substrate is formed with a wheel having a hardness higher than that of glass. A breaking process is then performed in which the LCD panels are cut by applying a mechanical force along the scribing line.
The apparatus for cutting a liquid crystal panel and method thereof will now be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic plan view illustrating a unit liquid crystal display panel formed with a thin film transistor array substrate and a color filter substrate 2 attached to face into each other in accordance with the related art.
In FIG. 1, the liquid crystal display panel 10 includes an image display unit 13 having a plurality of liquid crystal cells arranged in a matrix. A gate pad unit 14 connects to a plurality of gate lines of the image display unit 13. In addition, a data pad unit 15 connects to a plurality of data lines.
The gate pad unit 14 and the data pad unit 15 are formed at a marginal portion of a thin film transistor array substrate 1. The gate pad unit 14 on thin film transistor array substrate does not overlap the color filter substrate 2. The gate pad unit 14 supplies a scan signal supplied from a gate driver integrated circuit to the gate lines of the image display unit 13. The data pad unit 15 supplies image information supplied from a data driver integrated circuit to the data lines of the image display unit 13.
The data lines receiving the image information and the gate lines receiving the scan signal are disposed such that the data lines and the gate lines orthogonally cross on the thin film transistor array substrate 1 of the image display unit 13. At the crossed portion, a thin film transistor is formed for switching the liquid crystal cells, and a pixel electrode is formed that connects to the thin film transistor for driving the liquid crystal cell. Further, a passivation layer is formed on the entire surface to protect the electrode and the thin film transistor.
At the color filter substrate 2 of the image display unit 13, a plurality of color filters are separated into regions by a black matrix. In addition, a common transparent electrode corresponding to the pixel electrode is formed on the thin film transistor array substrate 1.
A cell gap is formed between the thin film transistor array substrate 1 and the color filter substrate 2 so that the two substrates are spaced apart and face each other. The thin film transistor array substrate 1 and the color filter substrate 2 are attached by a sealant (not shown) formed at the exterior of the image display unit 13. A liquid crystal layer (not shown) is formed at the space between the thin film transistor array substrate 1 and the color filter substrate 2.
FIG. 2 is a cross-sectional view showing a plurality of unit liquid crystal display panels formed in the first mother substrate having the thin film transistor array substrate and the second mother substrate with the color filter substrate in accordance with the related art.
As illustrated in FIG. 2, a plurality of unit panels are formed in such a manner that one side of the thin film transistor array substrate 1 protrudes beyond the edge of the corresponding color filter substrate 2. This protrusion of the thin film transistor array substrate corresponds to dummy region 21 of the color filter substrate 2. This occurs because the gate pad unit 14 and the data pad unit 15 are formed at the marginal portion where the thin film transistor array substrate 1 and the color filter substrate 2 do not overlap, i.e., the extend portion of the thin film transistor array substrate.
Thus, the color filter substrate 2 formed on the second mother substrate 30 is isolated from an area on the thin film transistor array substrate 1 formed on the first mother substrate 20 that corresponds to the color filter substrate 2 by the amount the dummy regions 21 protrude.
Each unit panel is disposed at the first and second mother substrates 20 and 30 such that space on the first and the second mother substrates 20 and 30 is maximized. Depending on the model, the unit panels are generally formed to be isolated by an amount corresponding to a dummy region 22.
After the first mother substrate 20 having the thin film transistor array substrates 1 is attached to the second mother substrate 30 having the color filter substrates 2, the liquid crystal display panels are individually cut using both the scribing process and the breaking process. The dummy regions 21 formed where the color filter substrates 2 of the second mother substrate 30 are isolated are removed. The dummy regions 22 isolating the unit panels are simultaneously removed.
The process of cutting the unit panels will now be described with reference to FIGS. 3A to 3H.
As illustrated in FIG. 3A, first scribing lines 31 for dividing the plurality of liquid crystal display panels 10 in a first direction are sequentially formed as the mother substrate 20 having the plurality of liquid crystal display panels 10 moves in one direction.
Next, as illustrated in FIG. 3B, the mother substrate 20 rotates 90°. While the mother substrate 20 moves back to its original position, second scribing lines 32 for dividing the plurality of liquid crystal display panels 10 in a second direction are sequentially formed.
As illustrated in FIG. 3C, the mother substrate 20 is flipped and struck by a breaking bar 40 by moving the mother substrate 20 in one direction. As such, a crack is formed on the mother substrate 20 along the second scribing line 32.
Next, as illustrated in FIG. 3D, the mother substrate 20 rotates 90° and is struck by the breaking bar 40 by moving the mother substrate 20 back to its original position. Thus, a crack is formed on the mother substrate 20 along the first scribing line 31.
As illustrated in FIG. 3E, while the mother substrate 20 is moved in one direction, third scribing lines 33 that divide the plurality of liquid crystal display panels 10 in a first direction are sequentially formed.
Next, as illustrated in FIG. 3F, the mother substrate 20 rotates by 90°. Then, as the mother substrate 20 moves back to its original position, fourth scribing lines 34 for dividing the plurality of liquid crystal display panels 10 in a second direction are sequentially formed.
As illustrated in FIG. 3G, the mother substrate 20 is flipped over and struck by a breaking bar 41 by moving the mother substrate 20 to its original position. Thus, a crack is formed on the mother substrate 20 along the fourth scribing line 34.
As illustrated in FIG. 3H, the mother substrate 20 is rotated by 90° and is struck by the breaking bar 41 by moving the mother substrate 20 to its original position such that a crack is formed on the mother substrate 20 along the third scribing line 33.
In a related art cutting apparatus and method for forming a unit LCD panel, a scribing process and a breaking process are done four times while performing four rotation processes and two flipping processes.
Thus, two scribing units that include a rotating unit and two breaking units that include a rotating unit and a flipping unit are required. This equipment occupies a great amount of space in the fabrication line. Thus, installation expenses and space occupied by the equipment increase.
In addition, this related art apparatus and method increases the time associated with the scribing and breaking processes, thereby resulting in low productivity.
A related art method for simultaneously fabricating LCD panels having different sizes on a mother substrate will be explained in more detail as follows.
For example, when single size LCD panels are fabricated on a mother substrate, a region where the LCD panels are not fabricated is discarded thereby wasting an unused portion of the mother substrate.
Therefore, LCD panels having a smaller size than the single size LCD panels are fabricated on regions of the mother substrate where the single size LCD panels are not fabricated. This method utilizes the space on a mother substrate, thereby increasing efficiency.
However, in the related art cutting apparatus and method for forming the unit LCD panel, a breaking process cannot be performed where a mother substrate includes LCD panels having different sizes.
The related art cutting apparatus and method for cutting the unit LCD panel will be explained with reference to the attached drawings in more detail.
FIGS. 4A to 4H are related art views sequentially showing a cutting method of a unit LCD panel with a cutting apparatus where LCD panels of different sizes are fabricated on one mother substrate.
As illustrated in FIG. 4A, while a mother substrate 100 having LCD panels 110 of a first size and LCD panels 120 of a second size moves in one direction, first scribing lines 131 for dividing the LCD panels 110 of the first size and the LCD panels 120 of the second size in a first direction are sequentially formed.
Afterwards, as illustrated in FIG. 4B, the mother substrate 100 is rotated by 90°. Then, while the mother substrate 100 moves back to its original position, second scribing lines 132 for dividing the plurality of liquid crystal display panels 110 of the first size and the LCD panels 120 of the second size in a second direction are sequentially formed.
As illustrated in FIG. 4C, the mother substrate 100 is flipped over and moved in one direction. The mother substrate 100 is struck by a breaking bar 140 such that a crack is formed on the mother substrate 100 along the second scribing line 132.
However, in the process, image display regions of the LCD panels 110 of the first size are damaged by the breaking bar 140 thereby creating an inferior product.
As illustrated in FIG. 4D, the mother substrate 100 is rotated by 90° and struck by the breaking bar 140 while moving the mother substrate 100 to its original position. As such, a crack is formed on the mother substrate 100 along the first scribing line 131.
As illustrated in FIG. 4E, while the mother substrate 100 moves in one direction, third scribing lines 133 for dividing the LCD panels 110 of the first size and the LCD panels 120 of the second size in a first direction are sequentially formed.
As illustrated in FIG. 4F, the mother substrate 100 rotates by 90°. Then, while the mother substrate 100 moves back to its original position, fourth scribing lines 134 for dividing the plurality of liquid crystal display panels 110 of the first size and the LCD panels 120 of the second size in a second direction are sequentially formed.
As illustrated in FIG. 4G, the mother substrate 100 is flipped over and moved in one direction. The mother substrate 100 is struck by a breaking bar 141 such that a crack is formed on the mother substrate 100 along the fourth scribing line 134.
However, in this process, image display regions of the LCD panels 110 of the first size are damaged by the breaking bar 141 thereby creating an inferior product.
As illustrated in FIG. 4H, the mother substrate 100 is rotated by 90° and struck by the breaking bar 141 by moving the mother substrate 100 to its original position. Thus a crack is formed on the mother substrate 100 along the third scribing line 133.
As aforementioned, in this related art cutting apparatus and method, a scribing process and a breaking process are done four times while performing four rotation processes and two turning processes. Thus, two scribing units that include a rotating unit and two breaking units that include a rotating unit and a flipping unit are required. This equipment occupies a great amount of space in the fabrication line. As such, installation expenses and space occupied by the equipment increase.
In addition, additional time is required for the scribing and breaking processes, thereby decreasing productivity.
Furthermore, in a related art cutting apparatus and method for a unit LCD panel, a breaking process cannot be easily performed where LCD panels having different sizes are fabricated on a mother substrate.